Autoimmune chron ic active hepatitis (CAH) and primary sderosing cholangitis (PSC) arc chronic diseases of the hepatobiliary system that have many cli nica l, immunologic and genetic features in commo n. Despite these similarities, there are few reports of the two diseases coexisting. Two young women with clinical, biochemical, serologic, radiologic and histologic findings compatible with both autoimmune CAH and PSC are described. The observation that there may be a striking overlap in the featu res of these two diseases and recent improvements in diagnostic imaging of the biliary tract suggest that the association of these two diseases in the same individual may be more common than is presently appreciated. Can J Gastroentero l 1988; 2(1): 22-27